Solid state electronic compact microwave and millimeter-wave ("MM") radars would be useful in many applications, such as in automobiles for detecting the speed and position of other vehicles and objects.
Generally, such radars contains three main components: a transceiver for generating and receiving MM electromagnetic ("EM") radiation, an antenna for collimating and focusing the radiation, and a feed assembly for coupling the radiation from the transceiver to the antenna. In addition to collimating and focusing the emitted radiation, the antenna also receives and focuses the radiation reflected from detected objects, and provides it to the transceiver.
The transceiver comprises primarily a transmission portion and a receiving portion. The transmission portion generates the radiation and the receiving portion receives the radiation reflected from the target and provides output signals from which useful information such as the speed and position of the detected objects can be determined.
An automobile radar should be small in size, to be conveniently mounted in a vehicle, and should preferably have sufficient power to detect targets at about 150 meters away or such other distance as the particular application may require. Additionally, the total power consumed by the radar should be low, e.g. in the range of several watts.
Another important requirement for automobile radar is that the diameter of the emitted radiation beam at a certain distance should be small enough (in relation to the target size) to accurately determine the position of detected object. It is also preferable that such radar be manufactured at a low cost in mass quantities.
Available radars suffer several limitations that make them unsuitable for automobile use. For example, their radiation beam diameter at a distance from the radar is generally dependent on the diameter of its antenna. Thus, larger antennas are required to produce smaller beam diameters. Accordingly, a sufficiently high resolution radar requires a large antenna, so that its size is impractical for automobile applications.
Additionally, in radars having multi-directional beams for performing spatial scanning, which are the kind of radars required for automotive applications, increasing the antenna diameter for higher resolution also requires increasing the longitudinal dimension of the radar, which makes it more difficult to utilize such radar for automotive applications.
Due to these limitations, currently available MM-wave radars used on some large vehicle such as buses have antenna diameters of 11 inches and can only resolve a vehicle at a maximum distance of 50 meters, and therefore are not satisfactory for practical application in automobiles or comparable vehicles.
It is therefore an object of the present invention to provide a compact MM wave radar that is small in size, has adequate range and resolution, consumes little power, and can be manufactured in mass quantities at low cost.
It is a further object of the present invention to provide an antenna including a lens, where the longitudinal dimension of the antenna is less than the focal length of the lens alone;
It is a further object of the present invention to provide a compact transceiver-feed assembly;
It is still a further object of the present invention to provide a heat sink for the transceiver-feed assembly as part of the antenna system.